For the scenarios of Our-1B and Our-2B by using \(d_4=0.82\) , the branching ratios from the full amplitudes, look larger than the results from the scenarios of Our-1A and Our-2A by taking \(d_4=-0.12\) . Nevertheless, for a given photon energy cutoff, the orders of magnitudes from different scenarios remain the same. According to the Belle-II estimate [1]}, around 45 billion pairs of the \(\tau \)  leptons will be collected. Hence we anticipate that the radiative two-pion \(\tau \)  decay processes have the good chance to be measured by the Belle-II experiment.
